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Acta Pharmaceutica Sinica B 2018年第3期8卷 360-370页

作者： Li Tian Linfeng Lu James Feng Marites P.Melancon Department of Interventional Radiology The University of Texas MD Anderson Cancer Center Duke University Graduate School of Biomedical Sciences University of Texas Health Science Center at Houston

A review of radiopaque nano and polymeric materials for atherosclerosis imaging and catheterization procedures is presented in this paper. Cardiovascular diseases(CVDs) are the leading cause of death in the US with atherosclerosis as a significant contributor for mortality and morbidity. In this review paper, we discussed the physics of radiopacity and X-ray/CT, clinically used contrast agents,and the recent progress in the development of radiopaque imaging agents and devices for the diagnosis and treatment of CVDs. We focused on radiopaque imaging agents for atherosclerosis, radiopaque embolic agents and drug eluting beads, and other radiopaque medical devices related to catheterization procedures to treat CVDs. Common strategies of introducing radiopacity in the polymers, together with examples of their applications in imaging and medical devices, are also presented.

关键词： Radiopaque contrast nanoparticles and materials X-ray CT Vascular diseases Atherosclerosis Plaque Stenosis Embolization Inferior vena cava filters

Optimizing film thickness to delay strut fracture in high-entropy alloy composite microlattices

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International Journal of Extreme Manufacturing 2021年第2期3卷 107-112页

作者： james Utama Surjadi Xiaobin feng Wenzhao Zhou Yang Lu Department of Mechanical Engineering City University of Hong KongKowloonHong Kong Special Administrative Region of China Nano-Manufacturing Laboratory(NML) City University of Hong Kong Shenzhen Research InstituteShenzhen 518057People’s Republic of China

Incorporating high-entropy alloys(HEAs) in composite microlattice structures yields superior mechanical performance and desirable functional properties compared to conventional metallic lattices. However, the modulus mismatch and relatively poor adhesion between the soft polymer core and stiff metallic film coating often results in film delamination and brittle strut fracture at relatively low strain levels(typically below 10%). In this work, we demonstrate that optimizing the HEA film thickness of a CoCrNiFe-coated microlattice completely suppresses delamination,significantly delays the onset of strut fracture(~100% increase in compressive strain),and increases the specific strength by up to 50%. This work presents an efficient strategy to improve the properties of metal-composite mechanical metamaterials for structural applications.

关键词： high-entropy alloy microlattice mechanical metamaterials microstructure thin film

China's Investments in Skills

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Frontiers of Economics in China-Selected Publications from Chinese Universities 2018年第4期13卷 531-558页

作者： james J.Heckman Shuaizhang feng Center for the Economics of Human Development University of ChicagoChicagoIL 60637USA Institute for Economic and Social Research Jinan UniversityGuangzhou 510632China

This paper discusses the benefits of investment in skills in China. We highlight the achievements China has made over time in human capital investments and the new challenges that have emerged as the country develops. To fuel China's further economic growth and social developments, it is essential to take a more holistic view on skill investments. We suggest policies that promote both economic efficiency and social mobility. [ABSTRACT FROM AUTHOR]

关键词： China human capital migration vocational training

Brain regulates weight bearing bone through PGE2 skeletal interoception: implication of ankle osteoarthritis and pain

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Bone Research 2024年第1期12卷 107-121页

作者： feng Gao Qimiao Hu Wenwei Chen Jilong Li Cheng Qi Yiwen Yan Cheng Qian Mei Wan james Ficke Junying Zheng Xu Cao Department of Orthopedic Surgery Johns Hopkins University School of MedicineBaltimoreMaryland 21205USA Department of Biomedical Engineering Johns Hopkins University School of MedicineBaltimoreMaryland 21205USA

Bone is a mechanosensitive tissue and undergoes constant remodeling to adapt to the mechanical loading environment.However,it is unclear whether the signals of bone cells in response to mechanical stress are processed and interpreted in the brain.In this study,we found that the hypothalamus of the brain regulates bone remodeling and structure by perceiving bone prostaglandin E2(PGE2)concentration in response to mechanical loading.Bone PGE2 levels are in proportion to their weight bearing.When weight bearing changes in the tail-suspension mice,the PGE2 concentrations in bones change in line with their weight bearing changes.Deletion of cyclooxygenase-2(COX2)in the osteoblast lineage cells or knockout of receptor 4(EP4)in sensory nerve blunts bone formation in response to mechanical loading.Moreover,knockout of TrkA in sensory nerve also significantly reduces mechanical load-induced bone formation.Moreover,mechanical loading induces cAMP-response element binding protein(CREB)phosphorylation in the hypothalamic arcuate nucleus(ARC)to inhibit sympathetic tyrosine hydroxylase(TH)expression in the paraventricular nucleus(PVN)for osteogenesis.Finally,we show that elevated PGE2 is associated with ankle osteoarthritis(AOA)and pain.Together,our data demonstrate that in response to mechanical loading,skeletal interoception occurs in the form of hypothalamic processing of PGE2-driven peripheral signaling to maintain physiologic bone homeostasis,while chronically elevated PGE2 can be sensed as pain during AOA and implication of potential treatment.

关键词： pain elevated PGE2

Implementation of Envelope Analysis on a Wireless Condition Monitoring System for Bearing Fault Diagnosis

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International Journal of Automation and computing 2015年第1期12卷 14-24页

作者： Guo-Jin feng james Gu Dong Zhen Mustafa Aliwan feng-Shou Gu Andrew D.Ball School of Computing and Engineering University of Huddersfield School of Engineering Manchester Metropolitan University

Envelope analysis is an effective method for characterizing impulsive vibrations in wired condition monitoring(CM)systems. This paper depicts the implementation of envelope analysis on a wireless sensor node for obtaining a more convenient and reliable CM system. To maintain CM performances under the constraints of resources available in the cost effective Zigbee based wireless sensor network(WSN), a low cost cortex-M4 F microcontroller is employed as the core processor to implement the envelope analysis algorithm on the sensor node. The on-chip 12 bit analog-to-digital converter(ADC) working at 10 k Hz sampling rate is adopted to acquire vibration signals measured by a wide frequency band piezoelectric accelerometer. The data processing flow inside the processor is optimized to satisfy the large memory usage in implementing fast Fourier transform(FFT) and Hilbert transform(HT). Thus, the envelope spectrum can be computed from a data frame of 2048 points to achieve a frequency resolution acceptable for identifying the characteristic frequencies of different bearing faults. Experimental evaluation results show that the embedded envelope analysis algorithm can successfully diagnose the simulated bearing faults and the data transmission throughput can be reduced by at least 95% per frame compared with that of the raw data, allowing a large number of sensor nodes to be deployed in the network for real time monitoring.

关键词： Wireless sensor network(WSN),envelope analysis,fault diagnosis,local processing,Hilbert transformation

Recent advances in plant centromere biology

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Science China(Life Sciences) 2015年第3期58卷 240-245页

作者： feng Chao LIU YaLin SU HanDong WANG HeFei BIRCHLER james HAN FangPu State Key Laboratory of Plant Cell and Chromosome Engineering Institute of Genetics and Developmental Biology Chinese Academy of Sciences University of Chinese Academy of Sciences Division of Biological Sciences University of Missouri-Columbia

The centromere, which is one of the essential parts of a chromosome, controls kinetochore formation and chromosome segregation during mitosis and meiosis. While centromere function is conserved in eukaryotes, the centromeric DNA sequences evolve rapidly and have few similarities among species. The histone H3 variant CENH3(CENP-A in human), which mostly exists in centromeric nucleosomes, is a universal active centromere mark in eukaryotes and plays an essential role in centromere identity determination. The relationship between centromeric DNA sequences and centromere identity determination is one of the intriguing questions in studying centromere formation. Due to the discoveries in the past decades, including "neocentromeres" and "centromere inactivation", it is now believed that the centromere identity is determined by epigenetic mechanisms. This review will present recent progress in plant centromere biology.

关键词：着丝粒生物学植物染色体分离 DNA序列真核生物减数分裂期组蛋白H3

Efficient Targeted Genome Modification in Maize Using CRISPR/Cas9 System

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Journal of Genetics and Genomics 2016年第1期43卷 37-43页

作者： Chao feng Jing Yuan Rui Wang Yang Liu james A. Birchler Fangpu Han State Key Laboratory of Plant Cell and Chromosome Engineering Institute of Genetics and Developmental Biology Chinese Academy of Sciences Beijing 100101 China University of Chinese Academy of Sciences Beijing 100049 China Division of Biological Sciences University of Missouri Columbia MO 65211-7400 USA

CRISPR （clustered regularly interspaced short palindromic repeats）/Cas9 system, which is a newly developed technology for targeted genome modification, has been successfully used in a number of species. In this study, we applied this technology to carry out targeted genome modification in maize. A marker gene Zmzb7 was chosen for targeting. The sgRNA-Cas9 construct was transformed into maize protoplasts, and indel （insertion and deletion） mutations could be detected. A mutant seedling with an expected albino phenotype was obtained from screening 120 seedlings generated from 10 callus events. Mutation efficiency in maize heterochromatic regions was also investigated. Twelve sites with different expression levels in maize centromeres or pericentromere regions were selected. The sgRNA- Cas9 constructs were transformed into protoplasts followed by sequencmg the transformed protoplast genomic DNA. The results show that the genes in heterochromatic regions could be targeted by the CRISPR/Cas9 system efficiently, no matter whether they are expressed or not. Meanwhile, off-target mutations were not found in the similar sites having no PAM （protospacer adjacent motif） or having more than two mismatches. Together. our results show that the CRISPR/Cas9 system is a robust and efficient tool for genome modification in both euchromatic and heterochromatic regions in maize.

关键词： CRISPR/Cas9 Targeted genome modification Heterochromatic region Maize

Modeling the Newtonian dynamics for rotation curve analysis of thin-disk galaxies

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Research in Astronomy and Astrophysics 2011年第12期11卷 1429-1448页

作者： james Q.feng C.F.Gallo Superconix Inc 2440 Lisbon AvenueLake ElmoMN 55042USA

We present an efficient, robust computational method for modeling the Newtonian dynamics for rotation curve analysis of thin-disk galaxies. With appropriate mathematical treatments, the apparent numerical difficulties associated with singularities in computing elliptic integrals are completely removed. Using a boundary element discretization procedure, the governing equations are transformed into a linear algebra matrix equation that can be solved by straightforward Gauss elimination in one step without further iterations. The numerical code implemented according to our algorithm can accurately determine the surface mass density distribution in a disk galaxy from a measured rotation curve （or vice versa）. For a disk galaxy with a typical flat rotation curve, our modeling results show that the surface mass density monotonically decreases from the galactic center toward the periphery, according to Newtonian dynamics. In a large portion of the galaxy, the surface mass density follows an approximately exponential law of decay with respect to the galactic radial coordinate. Yet the radial scale length for the surface mass density seems to be generally larger than that of the measured brightness distribution, suggesting an increasing mass-tolight ratio with the radial distance in a disk galaxy. In a nondimensionalized form, our mathematical system contains a dimensionless parameter which we call the ＂galactic rotation number＂ that represents the gross ratio of centrifugal force and gravitational force. The value of this galactic rotation number is determined as part of the numerial solution. Through a systematic computational analysis, we have illustrated that the galactic rotation number remains within 4-10% of 1.70 for a wide variety of rotation curves. This implies that the total mass in a disk galaxy is proportional to V02 Rg, with V0 denoting the characteristic rotation velocity （such as the ＂flat＂ value in a typical ro- tation curve） and Rg the radius of the galactic disk. The predicted total galactic mass of the

关键词： galaxy： disk -- galaxies： general -- galaxies： kinematics and dynamics -- galaxies： structure -- methods： numerical and analytical

Spectral analysis of new black hole candidate AT2019wey observed by NuSTAR

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Science China(Physics,Mechanics & Astronomy) 2022年第1期65卷 92-102页

作者： Ye feng XueShan Zhao LiJun Gou Yufeng Li james FSteiner Javier AGarc´ıa Yuan Wang Nan Jia ZhenXuan Liao HuiXian Li Key Laboratory for Computational Astrophysics National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China Harvard-Smithsonian Center for Astrophysics Cambridge MA 02138USA Cahill Centre for Astronomy and Astrophysics California Institute of TechnologyPasadena CA 91125USA Dr.Karl Remeis-Observatory and Erlangen Centre for Astroparticle Physics Bamberg 96052Germany School of Science Jimei UniversityXiamen 361021China

AT2019 wey is a new galactic X-ray binary that was first discovered as an optical transient by the Asteroid Terrestrial-impact Last Alert System(ATLAS)on December 7,2019.AT2019 wey consists of a black hole candidate as well as a low-mass companion star(M_(star)≤1.0 M_(■))and is likely to have a short orbital period(P_(orb)≤16h).Although AT2019 wey began activation in the X-ray band on March 8,2020,it did not enter the soft state during almost the entire outburst.In this study,we present a detailed spectral analysis of AT2019 wey in the low/hard state during its X-ray outburst on the basis of Nuclear Spectroscopic Telescope Array(Nu S T AR)observations.We obtain tight constraints on several of its important physical parameters by applying the state of the art relxill relativistic reflection model family.In particular,we determine that the measured inner radius of the accretion disk is most likely to have extended to the innermost stable circular orbit(ISCO)radius,i.e.,R_(in)=1.38^(+0.23)_(-0.16)R_(ISCO).Hence,assuming R_(in)=R_(ISCO),we find the spin of AT2019 wey to be a*~0.97,which is close to the extreme and an inner disk inclination angle of i~22°.Additionally,according to our adopted models,AT2019 wey tends to have a relatively high iron abundance of AFe~5A_(Fe,■)and a high disk ionization state of logξ~3.4.

关键词： NuSTAR black hole physics X-rays binaries-stars individual AT2019wey

Experimental study on the degree and damage-control mechanisms of fuzzy-ball-induced damage in single and multi-layer commingled tight reservoirs

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Petroleum Science 2023年第6期20卷 3598-3609页

作者： Chinedu J.Okere james J.Sheng Li-Kun Fan Xiao-Wei Huang Li-Hui Zheng Pan-feng Wei Bob L.Herd Department of Petroleum Engineering Texas Tech UniversityTXUSA College of Petroleum Engineering China University of Petroleum(Beijing)Beijing102249China China Changqing Oilfield Company CNPCXi'an710018ShaanxiChina Beijing LihuiLab Energy Technology Co. Ltd.Beijing102200China

Fuzzy-ball working fluids(FBWFs)have been successfully applied in different development phases of tight reservoirs.Field reports revealed that FBWFs satisfactorily met all the operational and reservoir damage control requirements during their application.However,the damage-control mechanisms and degree of formation damage caused by fuzzy-ball fluids have not been investigated in lab-scale studies so far.In this study,the degree of fuzzy-ball-induced damage in single-and double-layer reservoirs was evaluated through core flooding experiments that were based on permeability and flow rate indexes.Additionally,its damage mechanisms were observed via scanning electron microscope and energy-dispersive spectroscopy tests.The results show that:(1)For single-layer reservoirs,the FBWF induced weak damage on coals and medium-to-weak damage on sandstones,and the difference of the damage in permeability or flow rate index on coals and sandstones is below 1%.Moreover,the minimum permeability recovery rate was above 66%.(2)For double-layer commingled reservoirs,the flow rate index revealed weak damage and the overall damage in double-layer was lower than the single-layer reservoirs.(3)There is no significant alteration in the microscopic structure of fuzzy-ball saturated cores with no evidence of fines migration.The dissolution of lead and sulfur occurred in coal samples,while tellurium in sandstone,aluminum,and magnesium in carbonate.However,the precipitation of aluminum,magnesium,and sodium occurred in sandstone but no precipitates found in coal and carbonate.The temporal plugging and dispersion characteristics of the FBWFs enable the generation of reservoir protection layers that will minimize formation damage due to solid and fluid invasion.

关键词： Drilling Fracture Fuzzy-ball fluids Formation damage analysis Muti-layer tight reservoirs Permeability damage index Flow rate damage index